Implementation patterns – Behavior

John Von Neumann contributed one of the primary metaphors of computing a sequence of instructions that are executed one by one. This metaphor permeates most programming languages, Java included. The topic of this chapter is how to express the behavior of a program.

The patterns are:

Control Flow—Express computations as a sequence of steps.

Main Flow—Clearly express the main flow of control.

Message—Express control flow by sending a message.

Choosing Message—Vary the implementors of a message to express choices.

Double Dispatch—Vary the implementors of messages along two axes to express cascading choices.